Devices for producing sheets and tubes of fibrous cement or the like by winding a web of plastic mass of fibrous cement on to a sizing roll or a mandrel



Nov. 26, 1968 DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEMENTOR THE LIKE BY WINDING A WEB OF PLASTIC MASS OF FIBROUS CEMENT ON TO ASIZING ROLL OR A MANDREL Filed Feb. 18, 1965 K. A. OESTERHELD 7Sheets-Sheet l K. A. OESTE/mgm ATTys.

Nov. 26, 1968 K. A. OESTERHELD 3,413,191

DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEMEN OR THE LIKE BYWINDING A WEB OF PLASTIC MASS OF FIBRGUS CEMENT ON TO A SIZING ROLL OR AMANDREL Filed Feb. v18, 1965 7 Sheets-Sheet 2 T fu a QJ' E E nu/NrfNro/P Q u) k K. A. ESTf/ef/L Nov. 26, 1968 K. A. OESTERHELD3,413,191

DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEMENT OR THE LIKE BYWINDING A WEB OF PLASTIC MASS OF FIBROUS CEMENT ON TO A SIZING ROLL OR AMANDREL Filed Feb. 1a, 1965 7 sheets-sheet 5 K A OESTER//ELQ K. A.OESTERHELD Nov. 26, 1968 :NT CR THB LIKE BY WINDING A WEB OF PLASTICMASS OF FIBROUS DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEM'-CEMENT ON TO A SIZING ROLL OR A MANDREL 7 Sheets-Sheet Filed Feb. 18,1965 /NVEA/rop A. A. O55 nee/fno Arrxs.

NOV- 26, 1968 K. A. OESTERHELD 3,413,191

DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEMENT OR THE LIKE BYWINDING A WEB OF PLASTIC MASS OF FIBROUS CEMENT ON To A SIZING ROLL OR AMANDREL Filed Feb. 18, 1965 7 sheets-sheet s /NyENm/P A. A. 055716219540Nov. 26, 1968 K. A. OESTERHELD 3,413,191

DEVICES FOR PRODUCING SHEETS AND TUBES OF FIBROUS CEMENT GR THE LIKE BYWINDING A WEB OF PLASTIC MASS OF FIBROUS CEMENT ON TO A SIZING ROLL OR AMANDREL Filed Feb. 18, 1965 'T Sheets-Sheet 6 ATTYS.

Nov. 26, 1968 K. A. OESTERHELD DEVICES FOR PRODUCING SHEETS AND TUBES OFFIBROUS CEMENT OR THE LIKE BY WINDING A WEB OF PLASTC MASS OF FIBROUSCEMENT ON TO A SIZING ROLL OR A MANDREL Filed Feb. 18, 1965 7Sheets-Sheet 7 A TTYS.

United States Patent O 13 Claims. (l. 162-252) ABSTRACT OF THEDISCLOSURE This invention relates to devices for producing sheets andtubes of fibrous cement or the like, in which a web of plastic mass offibrous cement is wound in a plurality of layers on to a sizing roll ora mandrel, respectively, dewatered and compacted.

BACKGROUND OF THE INVENTION In the sheet producing machines which havebeen hitherto used in practice the sizing roll is rotated by astationarily mounted breast roll, which is driven at constant speed by amotor and supports the sizing roll mounted on vertically movablesupporting arms, through the intermediary of the web of fibrous cementfed between the breast roll and the sizing roll by a likewise drivenendless felt belt and transferred to the latter roll, and through thecoiled layers of web material already produced on the sizing roll. Theperipheral speed of the sizing roll, the outer diameter of which becomesincreasingly larger with the growing wall thickness of the hollow brouscement cylinder under construction, is equal to that of the breast roll.

In tube producing machines the mandrel is driven in a similar manner bythe endless felt belt through the web of fibrous cement fed by thelatter and through the coiled layers formed on the mandrel.

In the friction drive of the sizing roll or the mandrel, respectively,which in practice is generally used both in sheet and tube producingmachines, the mass of fibrous cement is effective as a powertransmitting medium in that a thrust present in the direction ofrotation of the breast roll and in the feed direction of the felt beltis acting on the web of fibrous cement being fed and on the alreadycoiled layers of web material and puts the sizing roll or the mandrelinto rotation. The thrust must not exceed a certain value which isdependent on the kind of fibrous cement mass being processed as -well ason the thickness of the web of fibrous cement on the felt belt, sinceotherwise there is a risk of structural distortions occurring in the webof fibrous cement to be coiled and in the already produced coiledlayers, and of the individual coiled layers not being uniformlycompacted, matted and dewatered. This has to be taken into considerationwhen rating the speed at which the web of fibrous cement is running onto the sizing roll or the mandrel. A faster production speed as isdesired for increasing the output and for economical reasons couldhitherto not be realized because the accomplishment of unobjectionablefinished products would then be no longer ensured.

Difficulties concerning production engineering are caused above all inthe manufacture of thick-walled hollow cylinders and tubes of fibrouscement by the fact that due to the thrust exerted by the breast roll andthe felt belt on the mass of fibrous cement the outer coiled layers arenot produced with the same homogeneity and the same surface finish asthe inner coiled layers. It has been found in practice that particularlythe edge portions of the finished sheets of fibrous cement and the endportions of the tubes of fibrous cement are not solidly enoughcompacted.

SUMMARY OF THE INVENTION It is the object of the present invention toshorten the production time for the hollow cylinders of fibrous cementintended for the production of sheets or to be manufactured as tubes andto improve, at the same time, the quality of the finished articles,especially of the thick-walled finished articles.

This object is achieved according to the invention by providing a methodof producing sheets and tubes of fibrous cement or the like, whichcomprises the steps of winding a web of plastic mass of fibrous cementin several layers on to a sizing roll or a mandrel, respectively,dewatering and compacting said web and transmitting during the winding,dewatering and compacting operations a torque, preferably a torquebecoming increasing larger with the growing wall thickness of the hollowcylinder of fibrous cement under construction, directly to the sizingroll or the mandrel, respectively, so that vduring the winding operationthe sizing roll or the mandrel, respectively, exerts a force on the massof fibrous cement that reduces or cancels the thrust exerted on the massof fibrous cement by a breast roll driven at constant speed and by a Webtransporting belt or becomes effective as tensile force when furtherincreasing the driving torque, by which tensile force the fibresoriented in the winding direction and the individual coiled layers areprestressed.

Since thus the mass of fibrous cement is at least partly or even fullyrelieved, during the winding operation, from the thrust acting in thewinding direction, the speed of building up the hollow cylinder offibrous cement can be increased without thus involving the risk ofdamaging by deformation the web of fibrous cement running on to thesizing roll or the mandrel and the coiled layers already formed. By themethod according to the invention the fed web of fibrous cement is woundon to the sizing roll or the mandrel, firmly pressed together with thepreviously formed coiled layers while being dewatered, and connectedwith them to form a hollow cylinder of fibrous cement which is uniformlyhomogeneous in all layers and also of compact structure in the two endportions. Generally, the advantages of the method as proposed by theinvention come into pl-ay best when the torque driving the sizing rollor the mandrel becomes larger with the growing wall thickness of thehollow fibrous cement cylinder under construction. This ensures that theouter layers of web material are wound on the sizing roll or the mandrelin as tight and firm a manner as the inner layers so that the finishedhollow cylinders of fibrous cement show no differences in structure andcompactness. In some cases it may be expedient for the condition of thematerial to be processed and for its filling material as well as for thepressure action on the sizing roll, which is necessary in particularcases, to drive the sizing roll or the mandrel with a constant or evendecreasing torque during the whole winding operation.

If the torques driving, on the on hand, the breast roll and the feltbelt and, on the other hand, the sizing roll or the mandrel are adjustedto one another so that the force exerted on the mass of fibrous cementby the sizing roll or the mandrel is greater than the thrust with whichthe breast roll and the felt belt act on the fibrous cement material,then the fibres lying in the longitudinal direction of the web offibrous cement and the individual coiled layers will be given anoptionally adjustable initial tension. In this way, finished productsare obtained that are distinguished by increased strength.

The method as proposed by the invention can be carried out in variousways. One of the possibilities coming into question for practicaloperation consists in controlling the transmission of torque independence on the variation of speed of the sizing roll or the mandrelthat occurs during the growing of the wall thickness of the hollowcylinder f fibrous cement under construction. In this case the sizingroll or the mandrel may be driven either by an electric motor or ahydraulic motor and the driving `power may be transmitted by a Cardanshaft, a flexible shaft, a V-belt drive or a similar transmission withor without interposition of a mechanical or magnetic clutch.

In the case of an electrical drive, it is expedient to use as a drivingmotor for the sizing roll or the mandrel an electric motor the currentconsumption of which adjusts itself automatically in accordance with therising torque with the aid of a tacho-generator connected to the shaftof the breast roll or of the driving motor of the breast roll. Brut theelectric driving motor may also be controlled, for example, by means ofa camshaft connected with the shaft of the sizing roll or the mandrelthrough a disengageable clutch.

In the case where a hydraulic drive is used for the sizing roll -or themandrel, regulating means serving to inuence the hydraulic fluid circuitof the hydraulic motor may be controlled either also in dependence onthe speed of the shaft of the sizing roll or the mandrel e.g. by meansof a centrifugal governor, a camshaft or the like, or in dependence onthe lifting motion of swinging arms supporting the sizing roll or themandrel.

According to a further suggestion of the invention, a direct control ofthe regulating means in the hydraulic liuid circuit of the hydraulicmotor by means of a time switch may be provided.

Brief description of drawings Several embodiments of devices forcarrying out the method according to the invention will now be describedby way of example and with reference to the accompanying drawings, inwhich:

FIG. l is a schematic side elevational view of the details of a sheetproducing machine with an electric motor drive for the sizing roll thatare necessary for the understanding of the invention;

FIG. ,2 is a circuit diagram of the self-regulating electric motor drivefor the sizing roll;

FIGS. 3 and 4 are a schematic side elevational view and a schematicfront elevational view, respectively, of the sizing roll and the breastroll, showing a hydraulic drive for the sizing roll;

FIG. 5 is a schematic side elevational view showing the control of thehydraulic drive for the sizing roll with the aid of a centrifugalgovernor;

FIG. 6 is a layout diagram of the hydraulic drive of FIG. 5;

FIG. 7 is a schematic side elevational view showing the control of thehydraulic drive for the sizing roll in dependence on the lifting motionof the swinging arms supporting the sizing roll;

FIG. 8 is a layout diagram of the hydraulic drive of FIG. 7, and

FIG. 9 is a schematic side elevational view showing the control of thehydraulic drive by a time switch.

Description of specific embodiment FIG. 1 shows a sheet producingmachine which comprises, as is customary, a winding or sizing roll 1having a shaft 2 rotatably mounted in bearings 5 on two supporting arms4 vertically swingable about fixed fulcrums of a frame 3, and a breastroll 6 having a shaft 7 mounted in bearings of the frame 3 so as to berotatable but immovable in height. The vertically movable sizing roll 1bears against the breast roll 6 which is provided with a smallerdiameter, and in addition to the force exerted by its dead weight it isrmly pressed against the breast roll 6 by an external force. For thispurpose two hydraulically or pneumatically operated working cylinders 9vare provided which are pivoted to arms 3a of the frame 3 and havepiston rods 10 hingedly connected to the ends of the double lever-typesupporting arms 4 remote from the sizing roll 1. The additional contactpressure of the sizing roll 1 can be optionally adjusted according torequirements by varying the pressure uid supply to the working cylinders9.

A web of fibrous cement can be conveyed to the sizing roll 1 by means ofa conveniently -driven endless felt belt 11 arranged to travel in aknown manner over one or more containers (not shown) in which sievedrums and couch-rolls are disposed for applying a plastic mass offibrous cement on to the downwardly directed side of the lower run ofthe endless felt belt 11, couching the applied mass and precompressingit.

The upper run of the felt belt 11 is arranged to pass over a suction box12 serving to suck part of the moisture out of the web of brous cement.On the downstream side of the suction box 12 the felt belt 11 isadvanced to the sizing roll 1 over guide rollers 13 and then passedthrough between the sizing roll 1 and the breast roll 6. When passingthrough between the sizing roll and the breast roll the felt belttransfers the web of ibrous cement, which is positioned on its upperside, to the sizing roll 1 on which a hollow cylinder 8 of fibrouscement is formed of the individual coiled layers of web material.

The felt belt 11 is passed on over the breast roll 6 and after havingbeen passed round a return roller 14 it is guided over a cleaning devicewhich may comprise, for example, felt beaters 15 and spray nozzles, andin a clean state it is passed over a plurality of guide rollers 16 toreach again the sieve cylinders from which it can then take up again wetmass of fibrous cement.

The breast roll 6 is driven by a variable electric motor mounted on abracket and having a reduction gearing 81. A belt 82 transmits drivingpower to the shaft 7 of breast roll 6. The speed of the driving motorand thus the peripheral speed of the breast roll can be adjusted inaccordance with the kind of ibrous cement material to be processed andwith the kind of the products to be manufactored.

The above-described details of the sheet producing machine .are known.In accordance with the invention a special drive is provided for thesizing roll 1, which can be realized in various ways, as will behereinafter explained more specifically by reference to exemplifiedembodiments.

In FIGS. 1 and 2 the driving motor 80 of the breast roll 6 drivesthrough a belt 17a tacho-generator 18 capable of generating a constantalternating voltage corresponding to the constant motor speed. Thealternating voltage of the tacho-generaor 18 can be transformed into adirect voltage by a rectifier 19 (FIG. 2). The direct voltage which isproportional to the speed of the driving motor 80 is used for energizinga generator 20, the armature voltage of the generator 20 beingproportional to the speed of the electric motor 80 which drives thebreast roll 6 and the tacho-generator 18 and regulable by means of aregulating resistance 21. The actual number of revolutions per minute ofthe breast roll 6 can be read on a voltmeter 22 calibrated as a speedindicator and is accurately adjustable by means of a regulatingresistance 23 to the speed given in each case by the breast roll 6.

The sizing roll 1 is driven by a D.C. motor 24 which can be energized bythe voltage generated by the generator 20. A driving motor 25 isconnected to a power supply system lwhich feeds also the driving ymotor80 of the breast roll 6. A rectier 26 having a regulating resistance 27is connected to the power supply system to produce a direct voltage of,for example, volts which serves for exciting the eld voltage of the D.C.motor 24, also in this case a regulating resistance 28 being connectedin the lead. As the armature voltage of the generator 20 is proportionalto the speed of the motor 80 driving the breast roll 6, the powertransmission from the driving motor 24 to the sizing roll 1 is dependenton the speed of the driving motor 80 for the breast roll and of thetacho-generator 18 connected to said motor 80.

When the web of fibrous cement is wound in several layers on to thesizing roll 1, then the outer diameter of the sizing roll 1, whichresults from the jacket diameter of the sizing roll 1 and from thecoiled layers applied thereto, grows with each revolution. Since thesizing roll 1 is not to vary its peripheral speed, the speed of theelectric motor 24 driving the sizing roll will have to slightly decreasewith each revolution. The D.C. motor 24 is not capable of varying itsspeed by itself. The decrease of speed is brought about by the fact thatthe sizing roll 1 or the coiled layers already applied thereto is orrespectively are in frictional engagement with the web of fibrous cementwhich is fed by the felt belt 11, so that, consequently, the peripheralspeed of the sizing roll 1 must be the same as that of the breast roll6.

Due to the decrease of the speed of the D.C. motor 214 driving thesizing roll 1, the counter-electromotive force in the D.C. motor 24decreases whereas the current consumption through the armature of theD.C. motor increases accordingly. With the increased power consumption,which is controlled by the voltage of the tacho-generator 18 and by themode of operation of the generator 20, the D.C. motor 24 produces anincreasingly augmenting torque as is required for winding the outerlayers of web material as tightly and firmly on the sizing roll 1 as theinner layers.

The D.C. motor 24 is arranged on a plate-like support member 29 securedto one of the vertically movable supporting arms 4 for the sizingroll 1. The D.C. motor 24 drives a worm gear comprising a worm 31 and aworm yWheel 32 through a V-belt drive 30. The worm 31 and the worm wheel32 are enclosed in .a gear housing 33 which is likewise arranged on theplate-like support member 29. From a V-belt pulley 34 seated on a commonshaft with the worm wheel 32, the torque is transmitted to the sizingroll 1 through an endless V belt 35 and a V-belt pulley 36 seated on theshaft 2 of the sizing roll 1.

In FIGS. 3 and 4 the sizing roll 1 is driven by a hydraulic motor 37which drives the shaft 2 of the sizing roll 1 through a reductiongearing 38. Pressure fluid is supplied to the hydraulic motor 37 througha conduit 39 and returns to a pressure oil tank through a conduit 40.

The layout diagram of the pressure oil circuit is apparent from FIG. 6and :will be explained in detail hereinafter. In the embodiment of FIGS.5 and 6 a worm wheel 41 is mounted on the shaft 2 of the sizing roll 1and drives a spindle 43 through a worm 42. Hinged to the spindle 43 arecentrifugal weights 44 the deflection of which is transmitted to a stoparm 46 through a rotatable ring 45. The stop .arm 46 is displaceablyguided on the spindle 43 by means of a guide sleeve 47 and serves ascontrol element for a feeler lever 49 of a pressure-regulating valve 50,which lever is provided with a sliding roller 48. A spring 51 of thepressure-regulating valve 50 causes the sliding roller 48 of the feelerlever 49 to bear against the stop arm 46. With increasing wall thicknessof the hollow cylinder lof fibrous cement being under construction onthe sizing roll 1, the speed of the sizing roll 1 decreases whereby thecentrifugal weights 44 come down and thus actuate thepressure-regulating valve 50 through the stop arm 46.

The control that results therefrom for the hydraulic drive is describedas follows by reference to the layout diagram of FIG. 6: An electricmotor 52 drives an axial piston pump S3 of known construction which isprovided with an swingable part 54 for adjusting the stroke volume.Adjustment of the swingable part 54 is effected by means of a pressureregulator 55 which is operatively connected with the pressure-regulatingvalve 50. The pump 53 is arranged to deliver pressure oil through thefeed conduit 39 to the hydraulic motor 37 which is thereby put intorotation. The oil issuing again from the hydraulic motor 37 through theconduit 40 is returned .to the tank 58 via a preloading valve 56 vand afilter 57.

The preloading valve 56 has the function of generating a small counterpressure in the hydraulic motor 37 to attain smooth running. In case thehydraulic motor 37 is blocked, the oil stream delivered by the pump 53flows directly off to the tank 58 through a pressure relief valve 59. Asthe pressure slowly rises due to the augmenting driving torque, anadjusting piston of the pressure-regulating valve 50 clears across-sectional area of the valve and permits a Small oil stream toarrive at a spring-loaded adjusting piston a of the pressure regulator55. If the volume of this oil stream is smaller than the passage througha by-pass throttle 60, then no adjustment of the stroke volume of theaxial piston pump 53 is effected so that the driving speed of thehydraulic motor 37 is not varied. But as soon as the quantity of oilflowing to the pressure regulator 55 becomes so large that it can nomore fiow off through the by-pass throttle 60 without pressure loss,then the oil stream will adjust the piston 55a of the pressure regulator55 against the action of a biased spring SSb and thus reduce the strokevolume of the pump 53. The pump now delivers a smaller quantity ofpressure oil per unit of time, which results in a decrease of thedriving speed of the hydraulic motor 37.

If for some reason or other the torque should decrease again, then thepressure in the conduit 39 to the hydraulic motor 37 would also drop.The adjusting piston of the pressure-regulating valve 50 then moves intothe shutoff position and there flows no more pressure oil to theadjusting piston 55a of the pressure regulator 55. The spring 55b of thepressure regulator 55 can thus restore the adjusting piston 55a into theposition in which the pressure oil is led off through the by-passthrottle 60. In this manner the swingable part 54 of the pressure oilpump 53 is swung out again to allow increased delivery of the pump.

This would take place, in particular, when the finished sheet of fibrouscement runs off the sizing roll 1. But then a three-way valve 61 whichis operable through a limit switch will take over immediately. The basicadjustment of the pressure regulator 55 is obtained by prestressing thespring 55b of the adjusting piston 55a or through the adjustment of thespring 51 of the pressure-regulating valve 50. The three-way valve 61which is incorporated in the feed conduit 39 serves for shutting downthe hydraulic motor 37 in that it deviates as a hydraulic switch the oilstream from the hydraulic motor 37 and returns it to the tank 58 whileby-passing the hydraulic motor 37. It would be suitable to operate alsothe three-way valve 61 by means of the contactor for the driving motorof the breast roll 6 through the intermediary of an auxiliary switch sothat in the event of trouble the hydraulic motor is stopped immediately.But, as a matter of course, the hydraulic motor 37 can also be stoppedby switching off the electric driving motor 52.

In the arrangement according to FIGS. 7 and 8 the control of theregulating means disposed in the pressure oil circuit is derived fromthe lifting movement of the supporting arms 4 for ythe sizing roll 1.For this purpose a cam rail 62 which is engaged by the sliding roller 48of the feeler lever 49 of the pressure-regulating valve 50 is secured tothe end of one of the two supporting arms 4 remote from the sizingroll 1. As the wall thicknessl of the hollow cylinder of fibrous cementon the sizing roll 1 increases, the cam rail 62 is moved downwardlythereby to operate the feeler lever 49 of the pressure-regulating valve50. In this case, analogously, the same control operations are caused totake place in the pressure oil circuit as they have been described indetail when explaining the layout diagram of FIG. 6.

FIG. 9 shows an exemplified embodiment for the direct control of theregulating means of the pressure fluid circuit by means of a time switchsuch as an electrically operated clock which is accommodated in a commonhousing 63 with an interlocking contactor and a timedelay relay. Thelayout of the oil circuit and the associated regulating means aresubstantially the same as in FIGS. 6 and 8. The only difference of thearrangement according to FIG. 9 consists in that a two-way valve 64 anda control pump 65 with an electric driving motor 66 are connected in thepressure oil system instead of the by-pass throttle 60 and thepressure-regulating valve 50, respectively. The electric driving motor52 for the piston pump 53 of variable stroke volume and the electricdriving motor 66 of the control pump 65 can be switched onsimultaneously by means of a master contactor controller.

To one of the supporting arms 4 for the sizing roll 1 a cam rail 67 issecured which is arranged to operate a limit switch 68 when the finishedsheet of brous cement runs off the sizing roll 1 and when the sizingroll 1 goes down toward the breast roll 6.

The limit switch 68 sets going the clock and simultaneously actuates theinterlocking contactor which closes the two-way valve 64. The controlpump 63 now delivers a small constant quantity of oil to the pressureregulator 55 which corresponds with regard to construction and operationto the pressure regulator 55 of the arrangement according to FIG. 6. Thepiston 55a of the pressure regulator 55 moving upwardly against theaction of the preloaded spring SSb adjusts the swingable part 54 of thepiston pump 53 of variable stroke volume so that the pump feeds pressureoil to the hydraulic motor 37 and transmits through the reductiongearing 38 a torque with an appropriate number of revolutions to thesizing roll 1. As the control pump 65 is acting during the wholeoperating time of the time switch with an increasingly augmentingpressure on the piston 55a of the pressure regulator 55, the drivingtorque generated in the hydraulic motor 37 becomes increasingly greater.

Switching off the time switch is effected by a microswitch 69incorporated in a device 70 for measuring the wall thickness of thehollow cylinder of fiborus cement being under construction on the sizingroll 1. The device for measuring the thickness operates in a knownmanner by means of a feeler roller adapted to travel along the surfaceof the hollow cylinder of fiborus cement.

When upon reaching the real size of the hollow cylinder of fibrouscement the microswitch 69 is operated and switches off the time switch,the interlocking contactor is actuated which causes the impulse forsevering the finished hollow cylinder of fibrous cement to be generated.At the same time the two-way valve 64 is moved by the interlockingcontactor into the open position in which the oil is displaced from t-hevalve housing and forced back into the tank 58 by the spring 55h of thepressure regulator 55. The three-way valve 61 incorporated in thepressure oil circuit, which is not shown in FIG. 9, is also operated sothat the oil supply to the hydraulic motor 37 is interrupted and the oilis caused to flow off into the tank 58.

After having been switched off, the time switch returns automaticallyinto the zero psition. Switching it on again is effected by the limitswitch 68.

Wth the aid of the time-delay relay accommodated in the housing 63 andby estalbishing a connection between the same and the microswitch 69 itis possible to temporarily adjust the individual operations to oneanother as desired in order to meet practical requirements.

I claim:

1. An apparatus for manufacturing plastic, fibrous cement sheets andtubes comprising:

(a) a vertically movable Winding roll having a surface for carrying saidfibrous cement,

(b) a breast roll located adjacent said winding roll,

(c) means directing an endless belt between said winding roll and saidbreast roll,

(d) a first driving means for driving said 4breast roll at a constantperipheral speed,

(e) a second driving means for providing a driving power to impart aperipheral speed to said winding roll,

(f) said endless belt carrying a web of a mass of plastic, fibrouscement and feeding layers of said web j to form a wall of said mass ontosaid winding roll whereby said wall has an increasing thickness as thewall is formed,

(g) a means pressing said winding roll against said breast roll andcompacting said web onto said winding roll,

(h) said second driving means including a control means for varying thesaid driving power as a function of said increasing thickness to therebycontrol said peripheral speed of said winding roll.

2. Apparatus for manufacturing plastic, fibrous cement sheets and tubes,comprising:

(a) a vertically movable winding roll having a shaft and a surface forcarrying said fibrous cement,

(b) a breast roll located adjacent said winding roll,

(c) means directing an endless belt between said winding roll and saidbreast roll,

(d) a first driving means for driving said breast roll at a constantperipheral speed,

(e) a second driving means for providing a driving power to impart aperipheral speed to said winding roll,

(f) said endless belt carrying a web of a mass of plastic, fibrouscement and feeding layers of said web to form a wall of said mass ontosaid winding roll whereby said wall has an increasing thickness as thewall is formed,

(g) a means pressing said winding roll against said breast roll andcompacting said web onto said winding roll thereby forming a hollow,fibrous cement cylinder by subjecting said wall to shear forces as theendless belt passes between the said winding roll and said breast rollwhen said rolls have different peripheral speeds,

(h) said second driving .means including a control means for varyingsaid driving power,

(i) said control means including a means for monitoring said increasingthickness of said wall,

(j) said control means further including a means responsive to saidmonitoring means for varying the said driving power as a function ofsaid increasing thickness to thereby control the amount of shear forcesto which the said wall is subjected.

3. An apparatus as defined in claim 2 wherein said second driving meansincludes an electric motor and said control means comprises atacho-generator means connected in series with said electric motor anddriven -by said first driving means,

said tacho-generator means controlling the power consumption responsiveto an increasing torque load resulting from the said increasingthickness.

4. An apparatus as defined in claim 2 wherein said second driving meanscomprises a hydraulic motor, gear means connecting said motor to saidwinding roll and a pressure fluid circuit means providing a flow offluid to said hydraulic motor, and

said control means regulates the flow of fiuid within said pressurefiuid circuit means to control the driving power of said hydraulicmotor.

5. An apparatus as defined in claim 2 wherein said means for monitoringincludes a feeler roller engaging said winding roll, said rolleractivates said control means in response to the increasing wallthickness,

said second driving means comprises a hydraulic motor, gear meansconnecting motor to said winding roll and a pressure fiuid circuit meansproviding a flow of fiuid to said hydraulic motor, and

said control means regulates the flow of fluid within said pressurefluid circuit means to control the driving power of said hydraulicmotor.

6. An apparatus as defined in claim 2 wherein said second driving meanscomprises a hydraulic motor, gear means connecting motor to said windingroll and a circuit means providing a pressure fluid supply to saidhydraulic motor,

said control means regulates the supply of fluid within said pressurefiuid circuit means to control the driving power of said hydraulicmotor,

said control means having a time switch, and further including meansresponsive to said time switch for shutting off said supply when saidmonitoring means has indicated the desired thickness of said wall hasbeen reached and said hollow cylinder has been removed.

7. An apparatus as defined in claim 3 wherein said electric motor is adirect current motor,

said control means including a generator means for generating thearmature voltage of said direct current motor, and

said control means further including means for connecting saidtacho-generator means for generating the field voltage for saidgenerator.

8. An apparatus as defined in claim 7 wherein said second driving meansincludes a reduction gearing means and means for connecting said gearingmeans in series with said direct current motor and said winding roll.

9. An apparatus as defined in claim 4 wherein said control meansincludes a pressure-regulating valve for controlling said ow of uid, afeeler lever for activating said valve, a centrifugal governor, and avertically movable stop arm interposed between said centrifugal governorand contacting said feeler lever for activating said valve,

said centrifugal governor being responsive to said shaft of said windingroll and activating said pressureregulating valve by way of the saidstop arm.

10. An apparatus as defined in claim 5 including a pair of verticallymovable swinging arms which support said winding roll,

said control means further includes a cam rail and a pressure-regulatingvalve for controlling the flow of fluid and a feeler lever,

said cam rail being located on one of said swinging arms and in contactwith said feeler lever,

said feeler lever being mounted within said pressureregulating valve,and

means for transmitting change in pressure to said pressure fluid circuitmeans,

11. An apparatus as defined in claim 6 wherein said control meanscomprises a control pump located in said pressure fluid circuit means,an electric motor for driving said control pump, a means connecting saidtime switch to said electric motor,

a piston pump having a variable stroke volume, said piston pump locatedin said pressure fuid circuit means and acting on a pressure regulatorhaving an adjusting piston means for acting on said piston pump,

said control pump delivering pressure oil to move said adjusting pistonmeans until said time switch stops powerY to said electric motor fordriving said control pump.

12. An apparatus as defined in claim 11 including a pair of supportingarms mounted on a frame and supporting said winding roll,

a limit switch mounted on said frame,

means for connecting said limit switch to activate said time switch, and

means for operating said limit switch being mounted on one of saidsupporting arms.

13. An apparatus as defined in claim 6 wherein said means for monitoringincludes a microswitch for disconnecting said time switch operably incontact with said wall having an increasing thickness.

References Cited UNITED STATES PATENTS 3,121,659 2/1964 Amanzio 162--284S. LEON BASHORE, Primary Examiner.

